
/* Copyright 1998 by the Massachusetts Institute of Technology.
 * Copyright (C) 2012 Marko Kreen <markokr@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting
 * documentation, and that the name of M.I.T. not be used in
 * advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 */

#include "ares_setup.h"

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_ARPA_NAMESER_H
#include <arpa/nameser.h>
#else
#include "nameser.h"
#endif
#ifdef HAVE_ARPA_NAMESER_COMPAT_H
#include <arpa/nameser_compat.h>
#endif

#include "ares.h"
#include "ares_dns.h"
#include "ares_data.h"
#include "ares_private.h"

int ares_parse_soa_reply(const unsigned char* abuf, int alen,
    struct ares_soa_reply** soa_out)
{
    const unsigned char* aptr;
    long len;
    char *qname = NULL, *rr_name = NULL;
    struct ares_soa_reply* soa = NULL;
    int qdcount, ancount;
    int status;

    if (alen < HFIXEDSZ)
        return ARES_EBADRESP;

    /* parse message header */
    qdcount = DNS_HEADER_QDCOUNT(abuf);
    ancount = DNS_HEADER_ANCOUNT(abuf);
    if (qdcount != 1 || ancount != 1)
        return ARES_EBADRESP;
    aptr = abuf + HFIXEDSZ;

    /* query name */
    status = ares__expand_name_for_response(aptr, abuf, alen, &qname, &len);
    if (status != ARES_SUCCESS)
        goto failed_stat;
    aptr += len;

    /* skip qtype & qclass */
    if (aptr + QFIXEDSZ > abuf + alen)
        goto failed;
    aptr += QFIXEDSZ;

    /* rr_name */
    status = ares__expand_name_for_response(aptr, abuf, alen, &rr_name, &len);
    if (status != ARES_SUCCESS)
        goto failed_stat;
    aptr += len;

    /* skip rr_type, rr_class, rr_ttl, rr_rdlen */
    if (aptr + RRFIXEDSZ > abuf + alen)
        goto failed;
    aptr += RRFIXEDSZ;

    /* allocate result struct */
    soa = ares_malloc_data(ARES_DATATYPE_SOA_REPLY);
    if (!soa) {
        status = ARES_ENOMEM;
        goto failed_stat;
    }

    /* nsname */
    status = ares__expand_name_for_response(aptr, abuf, alen, &soa->nsname, &len);
    if (status != ARES_SUCCESS)
        goto failed_stat;
    aptr += len;

    /* hostmaster */
    status = ares__expand_name_for_response(aptr, abuf, alen, &soa->hostmaster, &len);
    if (status != ARES_SUCCESS)
        goto failed_stat;
    aptr += len;

    /* integer fields */
    if (aptr + 5 * 4 > abuf + alen)
        goto failed;
    soa->serial = DNS__32BIT(aptr + 0 * 4);
    soa->refresh = DNS__32BIT(aptr + 1 * 4);
    soa->retry = DNS__32BIT(aptr + 2 * 4);
    soa->expire = DNS__32BIT(aptr + 3 * 4);
    soa->minttl = DNS__32BIT(aptr + 4 * 4);

    ares_free(qname);
    ares_free(rr_name);

    *soa_out = soa;

    return ARES_SUCCESS;

failed:
    status = ARES_EBADRESP;

failed_stat:
    ares_free_data(soa);
    if (qname)
        ares_free(qname);
    if (rr_name)
        ares_free(rr_name);
    return status;
}
